Problem: In this problem your goal is to sort an array consisting of n integers in at most n swaps. For the given array find the sequence of swaps that makes the array sorted in the non-descending order. Swaps are performed consecutively, one after another.

Note that in this problem you do not have to minimize the number of swaps — your task is to find any sequence that is no longer than n.

Input

The first line of the input contains integer n (1 ≤ n ≤ 3000) — the number of array elements. The second line contains elements of array: a0, a1, ..., an - 1 ( - 109 ≤ ai ≤ 109), where ai is the i-th element of the array. The elements are numerated from 0 to n - 1 from left to right. Some integers may appear in the array more than once.

Output

In the first line print k (0 ≤ k ≤ n) — the number of swaps. Next k lines must contain the descriptions of the k swaps, one per line. Each swap should be printed as a pair of integers i, j (0 ≤ i, j ≤ n - 1), representing the swap of elements ai and aj. You can print indices in the pairs in any order. The swaps are performed in the order they appear in the output, from the first to the last. It is allowed to print i = j and swap the same pair of elements multiple times.

If there are multiple answers, print any of them. It is guaranteed that at least one answer exists.

Examples

Input

5
5 2 5 1 4


Output

2
0 3
4 2


Input

6
10 20 20 40 60 60


Output

0


Input

2
101 100


Output

1
0 1

Solution (in JAVA):

Solution:
import java.awt.Point;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.StringTokenizer;


public class Solution{
	
	///////////////////////////////////////////////////////////////////////////
	static class FastScanner{
		BufferedReader s;
		StringTokenizer st;
		
		public FastScanner(InputStream InputStream){
			st = new StringTokenizer("");
			s = new BufferedReader(new InputStreamReader(InputStream));
		}
		
		public FastScanner(File f) throws FileNotFoundException{
			st = new StringTokenizer("");
			s = new BufferedReader (new FileReader(f));
		}
		
		public int nextInt() throws IOException{
			if(st.hasMoreTokens())
				return Integer.parseInt(st.nextToken());
			else{
				st = new StringTokenizer(s.readLine());
				return nextInt();
			}
		}
		
/*		public double nextDouble() throws IOException{
			if(st.hasMoreTokens())
				return Double.parseDouble(st.nextToken());
			else{
				st = new StringTokenizer(s.readLine());
				return nextDouble();
			}
		}
*/		
		public long nextLong() throws IOException{
			if(st.hasMoreTokens())
				return Long.parseLong(st.nextToken());
			else{
				st = new StringTokenizer(s.readLine());
				return nextLong();
			}
		}
		
		public String nextString() throws IOException{
			if(st.hasMoreTokens())
				return st.nextToken();
			else{
				st = new StringTokenizer(s.readLine());
				return nextString();
			}
			
		}
		public String readLine() throws IOException{
			return s.readLine();
		}
		
		public void close() throws IOException{
			s.close();
		}
		
	}
	
	////////////////////////////////////////////////////////////////////
	//		Number Theory
	
	long pow(long a,long b,long mod){
		long x = 1; long y = a;
		while(b > 0){
			if(b % 2 == 1){
				x = (x*y);
				x %= mod;
			}
			y = (y*y);
			y %= mod;
			b /= 2;			
		}
		return x;
	}
	
	int divisor(long x,long[] a){
	    long limit = x;
	    int numberOfDivisors = 0;

	    for (int i=1; i < limit; ++i) {
	        if (x % i == 0) {
	            limit = x / i;
	            if (limit != i) {
	                numberOfDivisors++;
	            }
	            numberOfDivisors++;
	        }
	    }
	    return numberOfDivisors;
    }
	
	void findSubsets(int array[]){
    	
	    long numOfSubsets = 1 << array.length; 
	    for(int i = 0; i < numOfSubsets; i++){
	    		
	    	int pos = array.length - 1;
	    	int bitmask = i;

	    	while(bitmask > 0){		
	    		if((bitmask & 1) == 1)
	   				ww.print(array[pos]+" ");
	    		
	   			bitmask >>= 1;
	        	pos--;
	    	}

	    	ww.println();
	   	}
	}
    
	
	public static long gcd(long a, long b){
		return b == 0 ? a : gcd(b,a%b);
	}
	
  
	public static int lcm(int a,int b, int c){
		return lcm(lcm(a,b),c);
	}
	
	public static int lcm(int a, int b){
		return (int) (a*b/gcd(a,b));
	}
	
	////////////////////////////////////////////////////////////////////
	
	
//	  private static  	FastScanner s = new FastScanner(new File("input.txt"));
//	  private static PrintWriter ww = new PrintWriter(new FileWriter("output.txt"));
	static InputStream inputStream = System.in;
	static FastScanner s = new FastScanner(inputStream); 
	static OutputStream outputStream = System.out;
    static PrintWriter ww = new PrintWriter(new OutputStreamWriter(outputStream));
//      private static Scanner s = new Scanner(System.in);
	@SuppressWarnings("unused")
	private static int[][] states = { {-1,0} , {1,0} , {0,-1} , {0,1} };
	
      
    //////////////////////////////////////////////////////////////////// 
      
     
    public static void main(String[] args) throws IOException{
 		new Solution().solve();
 		s.close();
		ww.close();
 	}
    
    
    ////////////////////////////////////////////////////////////////////
    
    int[] v;
    int[] z;
    
    void swap(int i, int j){
    	int swap = v[i];
    	v[i] = v[j];
    	v[j] = swap;
    }
    
	void solve() throws IOException{
		
		int n = s.nextInt();
		v = new int[n];
		z = new int[n];
		String[] ans = new String[10000];
		
		for(int i=0;i<n;i++){
			v[i] = s.nextInt();
			z[i] = v[i];
		}
		
		Arrays.sort(z);
		int cnt = 0;
		
		
		for(int i=0;i<n;++i){
			for(int j=i;j<n;++j)
				if(z[i]==v[j]){
					if(i!=j)
						ans[cnt++] = Integer.toString(i)+" "+Integer.toString(j);
					swap(i,j);
					break;
				}
		}
		
		ww.println(cnt);
		for(int i=0;i<cnt;i++) ww.println(ans[i]);
	}
}